I recommend using an existing app to collect the data. There are many alternatives, and since you are talking about medical students they should be able to follow simple instructions.
You probably have access to a full Adobe PDF creation suite. Create your form there with editable fields, checkboxes, etc. There are several apps for the iPad that will let you fill in this type of editable PDF including Adobe's own Adobe Reader (free). Others are PDF Expert and PDFPen.
When it comes time for them to fill it out, simply email them a copy of the form, along with instructions on how to fill it out and send it back. If you keep track of who has responded you can hammer the lazy ones with followup emails.
You'll want to test all the apps and procedure first, but I think this should work for you, and be much cheaper (and easier) than trying to develop your own app.
You could try the same thing with a spreadsheet app, for easier data retrieval on your end; but you'd probably need to buy the associated spreadsheet app for each student (or make them purchase it). I don't know of any good, free spreadsheet apps.